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Vulnerability · Published Oct 23, 2026 · Assigned by GitHub_M

CVE-2026-115776Twisted: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer

High 7.5

In plain English

A high-severity uncontrolled resource consumption in twisted from twisted. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 56.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.words.protocols.irc.IRC.dataReceived retains all bytes received without a line feed in its per-connection buffer and applies no maximum line length. The twisted.words.service.IRCUser server subclass inherits this behavior, and buffering occurs before PASS, NICK, or USER authentication commands. An unauthenticated connection can continuously grow the buffer until the shared server process runs out of memory and drops all users. This issue is fixed in version 26.10.0rc1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12twistedno fix listedDEBIAN-CVE-2026-115776
Debian:13twistedno fix listedDEBIAN-CVE-2026-115776
Debian:14twisted26.10.0-1DEBIAN-CVE-2026-115776
PyPItwisted26.10.0rc1GHSA-53xc-49m8-p798
Ubuntu:22.04:LTStwistedno fix listedUBUNTU-CVE-2026-115776
Ubuntu:24.04:LTStwistedno fix listedUBUNTU-CVE-2026-115776
Ubuntu:26.04:LTStwistedno fix listedUBUNTU-CVE-2026-115776
Ubuntu:26.10twistedno fix listedUBUNTU-CVE-2026-115776

Affected products (as reported)

VendorProductVersions
twisted twisted < 26.10.0rc1

Weakness: CWE-400, CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References